1. The problem statement, all variables and given/known data Determine the minimum positive value of the constant k needed to ensure that the function y(x) obeying x^2 y'' + K y = 0, y(1) = 0, y'(1)=1 will not simply keep on increasing toward large x but will instead return to cross y=o ocassionally 3. The attempt at a solution So far I've tried doing a change of variable and trnasform t= ln(X). The idea is that I should get a constant coefficient equation but do not know how to get there yet. I have tried using the chain rule twice to get from d^2y/dx^2 to d^2y/dt^2 but as said I do not seem to make any progress. Any ideas please?